1. Field of the Invention
The present invention relates to an electrical connector used to interconnect printed circuit boards, and particularly to such an electrical connector which is provided with an improved shield means.
2. Description of Prior Art
Backplane connectors are commonly used in backplane systems to electrically interconnect a daughter board or an inserted card to a backplane or a mother board which are substantially located at a right angle with respect to each other for transmitting high speed signals or data between the two boards. A backplane connector generally comprises a receptacle connector, usually named as a pin header, mounted on a backplane, and a plug connector mounted on a daughter board for mating with the receptacle connector. Such backplane connectors are disclosed in U.S. Pat. Nos. 5,993,259, 5,860,816 and 5,980,321. A receptacle connector comprises a plurality of wafers stacked side-by-side and each wafer includes a dielectric body, a number of signal terminals integrally formed in the dielectric body and a conductive shield covering on the dielectric body for providing Electro Magnetic Interference (EMI) shielding for the signal terminals of adjacent wafers. With the development trend in computers, backplane connectors are becoming more and more miniature while transmitting signals or logics with higher and higher speed in backplane systems, therefore, signal terminals of the backplane connector are becoming higher and higher in density. Therefore, to effectively overcome EMI or cross talk between adjacent signal terminals of the backplane connector is an important issue. However, the above-mentioned U.S. patents only disclose EMI shielding for the signal terminals between adjacent wafers by the conductive shield, but do not disclose EMI shielding between adjacent signal terminals within each wafer. Hence, a backplane connector with improved EMI shielding is desired.
A first object of the present invention is to provide an electrical connector which is provided with an excellent shielding function;
A second object of the present invention is to provide an electrical connector having a shielding mechanism which is easy manufactured and low in cost.
To fulfill the above-mentioned objects, an electrical connector in accordance with the present invention used in backplane systems comprises a plurality of wafers side-by-side staked with each other. Each Wafer includes a signal piece and a shield piece covered onto the signal piece. The signal piece is formed with a dielectric body and a plurality of signal terminals insert molded with the dielectric body. The dielectric body defines a plurality of through slots and a corresponding number of undercuts corresponding to the through slots both extending from one side to the other side thereof. The shield piece comprises a metal plate which is integrally formed with a plurality of first ribs and a corresponding number of second ribs corresponding to the first ribs formed through die-case for tightly insertion into corresponding through slots and undercuts of the signal piece, respectively. In addition, lower tip ends of the first ribs and top tip ends of the second ribs are overlapped or at least located on a common plane to effective block EMI among the signal terminals within each wafer.
Other objects, advantages and novel features of the invention will become more apparent from the following detailed description of the present embodiment when taken in conjunction with the accompanying drawings.